1 Make for the eastern end of Nettlebed High Street and turn left by the Pudding Stones. Follow the road round to the right, pass Chapel Lane and avoid a turning on the right. Keep left immediately beyond it at the fork, signposted 'Magpies'. Avoid a bridleway on the right and continue ahead towards Soundess House. The walk cuts through an avenue of trees, with glimpses here and there of glorious Chiltern country. Pass a footpath on the right and continue ahead into the trees when the track swings left at a footpath sign for Russell's Water.

2 Further on, merge with another track, avoiding a path on the left. Keep ahead, continue through the trees into a dry valley and soon a luxuriant curtain of trees rises up in front of you. Pass a picturesque, part timber-framed cottage on the left and turn left at the junction. Walk along to the Warburg Reserve Visitor Centre and car park.

3 Resuming the walk, continue ahead along the track. Eventually it parts company with the nature reserve, cutting between a line of trees and a fence. Avoid a track on the right and a stile on the left and head towards some farm outbuildings. Turn left just before the gate and go up the field slope to a stile in the trees on the right. Take the path through the woodland, climbing gently. Cross another stile and head straight across the field, looking for a stile up ahead.

4 Pass a pond set in the garden of a house, keep close to the left boundary and join a track. Turn left and follow it through the woodland. As the track curves right, go straight on along a path through the trees. The path veers left and climbs gently to a path. Cross over a clear path and keep ahead, following the white arrows on the tree trunks. On reaching a tree on the right with its trunk shaped like a Y, a few paces before an area of high ground drops away sharply, branch left and follow the path up to some fencing. Keep right of it and then turn right by some double gates to join a drive. Keep left at the next junction and return to the centre of Nettlebed.

The Warburg Reserve, a Site of Special Scientific Interest (SSSI) is a haven of woodland and grassland, which includes a wide variety of wildlife and a nature trail. Named after an Oxford botanist, the reserve lies either side of a dry, winding valley and the pooling of cold air along the valley floor means that from time to time very hard frosts strike this delightful, though remote, corner of the county.

Covering 262 acres (106ha) and acquired in 1967, Warburg is the largest reserve managed by the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust. Its mix of partly ancient woodland, scrub and flower-rich grassland has helped to establish the site as a major visitor attraction in the area in recent years. Warburg is especially famous for its flora, with more than 450 species of plants recorded, including 15 wild orchids. Forty different kinds of butterfly have been spotted here too, as well as 450 moths and 950 fungi.

Lizards, snakes, adders, doormice, moles, hares, deer, bats and badgers are also known to inhabit the reserve. If you have the time, call into the very informative visitor centre, sit in the adjoining bird hide and watch all manner of creatures visiting the pond. You could even extend the route by following the reserve's popular Wildlife Walk.

A number of trees within Warburg have been felled to create a graded interface between the grassy rides and the woodland. This produces one of the richest wildlife habitats here - attracting a wide variety of butterflies, including the dark green fritillary, the comma and the speckled wood. The felled trees leave spaces where sunlight can penetrate, with the remaining trees acting as windbreaks.

Much of the wildlife found at Warburg is struggling to survive generally throughout Britain. With increased pressure for more housing and changes in agricultural practices, the future of the countryside is under threat. Thankfully, Warburg acts as a sanctuary for wildlife - one of only a handful of sites in the country where such a rich collection of species still survives. The efforts of conservation volunteers are halting the decline of these precious plants and creatures. It is hoped that many will spread beyond the boundaries of Warburg and return to the natural habitat of the countryside.

Where to eat and drink

Nettlebed has the White Hart Hotel and the Sun Bistro. In nearby Highmoor is the Dog and Duck. If you want to stop for refreshments midway round the walk, the Warburg Reserve has a picnic area.

What to look for

The Pudding Stones, at the eastern end of the village street, were formed from various deposits of boulders and flint pebbles. The precise age, origin and purpose of the stones remain a mystery, though they survive as perfect examples of some of the most ancient works of primitive peoples.

While you're there

Have a look at one of Nettlebed's most famous landmarks, situated in a residential close near the village street. The village bottle kiln, preserved through public subscription and grants from charitable trusts, was restored in 1972.